1. Field of the Invention
The present invention relates to a surface mount connector mounted on a surface of printed circuit board, and more particularly, to a surface mount connector adapted to electrically connect a highly integrated electronic device such as a hard disc drive unit, IC memory card or the like to another device, wherein the drive unit and the memory card comprise a plurality of input and output pins or terminals.
2. Description of Prior Art
The number of input and output terminals of an integrated electronic device may, for example, be fifty to sixty-eight, with their contacts being disposed one above another to form two rows. Therefore, a pin header of the prior art surface mount connector for connection with such a device comprises a plurality of pairs of pin contacts 2 in a manner shown in FIGS. 9 and 10. They are arranged vertically and in two rows, wherein an upper pin contact 2A in each pair has a terminal pin 3 extending through an insulating housing 1 and located above another terminal pin 3 of a lower pin contact 2B. Leads 4A and 4B are respectively formed at the opposite end of the terminal pins 3. The lead 4A of the upper pin contact 2A in each pair has a length greater than a length of the other lead 4B of the lower pin contact 2B. Thus, the leads 4B of all the pairs form a inner row, and the other leads 4A form an outer row so that two rows of those leads are soldered to pads 33 on a printed circuit board 31.
It will however be noted that the soldered lead 4B of lower pin contact 2B in each pair is positioned behind the adjacent lead 4A of the upper pin contact 2A. This renders it difficult to perform the visual inspection of the soldered state of the inner leads 4B. Correction work for correcting any incorrectly soldered inner leads is also not easy.
On the other hand, the outer leads 4A extending beyond the inner leads 4B occupy an undesirably large area on a surface of the printed circuit board. Further, because the pin contacts 2A and 2B vertically disposed through the housing 1, the housing requires a height such that the connectors of this type cannot be made smaller and thinner.